/axiom-watchos

name: axiom-watchos
description: Use when building ANY watchOS app — app structure, independent apps, Watch Connectivity, Smart Stack widgets, complications, controls, RelevanceKit, background tasks, ClockKit migration.
license: MIT

watchOS Development

**You MUST use this skill for ANY watchOS-specific development including app structure, independent apps, Watch Connectivity, complications and Smart Stack widgets, controls, Live Activities on watch, background tasks, and ClockKit migration.**

<!-- AXIOM_AUDITOR_INLINE_BEGIN — rewritten for Codex by scripts/build-codex.ts; do not hand-edit --> > **Auditors are skills here.** Where this router says "Launch `some-auditor` agent", invoke the > matching Codex skill instead — same procedure, no Claude Code agent required. > > Available: `axiom-modernize`. > > The ones that shell out — builds, tests, simulators, crash symbolication — need shell access to run. <!-- AXIOM_AUDITOR_INLINE_END -->

Quick Reference

| Symptom / Task | Reference | |----------------|-----------| | App structure, independent apps, watchOS 26 submission requirements | See `skills/platform-basics.md` | | watchOS HIG, glanceable UX, navigation model | See `skills/design-for-watchos.md` | | Smart Stack widgets, complications, ClockKit→WidgetKit, RelevanceKit | See `skills/smart-stack-and-complications.md` | | Controls on watch surfaces, Live Activities on watch | See `skills/controls-and-live-activities.md` | | Watch Connectivity (WCSession), paired-device data transfer, Family Setup | See `skills/watch-connectivity.md` | | Xcode won't install/launch/attach to a Watch; Watch missing or `unavailable` in Device Hub / devicectl | See `skills/watch-device-diag.md` | | Background tasks, freshness scheduling, TN3135 networking limits | See `skills/background-and-networking.md` | | BGTaskScheduler migration, deprecated WK background scheduling `OS27` | See `skills/background-and-networking.md` | | Foundation Models / Private Cloud Compute on the watch `OS27` | See `skills/platform-basics.md` | | WatchKit→SwiftUI migration, ClockKit→WidgetKit migration | See `skills/modernization.md` |

Cross-Suite Routes

These topics overlap with watchOS development but live in separate suites:

SwiftUI (shared iOS/watchOS/macOS)

• View state, data flow, @Observable → See axiom-swiftui
• Navigation basics (NavigationStack) → See axiom-swiftui
• Layout, animations → See axiom-swiftui

Design

• General HIG, Liquid Glass, SF Symbols, typography → See axiom-design

Accessibility

• General VoiceOver, Dynamic Type, WCAG → See axiom-accessibility
• watchOS-specific (VoiceOver rotor on Digital Crown, AssistiveTouch, Double Tap) → See axiom-accessibility (`skills/watchos-a11y.md`)

Health and workouts

• HealthKit, `HKWorkoutSession`, `HKLiveWorkoutBuilder`, WorkoutKit → See axiom-health
• Workout recovery, multi-device coordination → See axiom-health (`skills/workouts.md`)

iOS-side widgets and App Intents

• iOS/iPadOS widgets, configuration intents, App Intents → See axiom-integration
• Live Activities on iPhone (initiation + ActivityKit) → See axiom-integration

Concurrency

• Swift 6 concurrency, actors, Sendable → See axiom-concurrency

New-on-watch frameworks (27 releases)

• Foundation Models depth (sessions, @Generable, tools, PCC) → See axiom-ai; watch scoping is in `skills/platform-basics.md`
• Vision framework (new on watchOS 27) → See axiom-vision
• NowPlaying / MusicUnderstanding (new on watchOS 27) → See axiom-media

Conflict Resolution

**axiom-watchos vs axiom-swiftui**: When building a watchOS SwiftUI app: 1. **Use axiom-watchos** for watch-specific patterns: glanceable UI, constrained navigation, Digital Crown focus, Smart Stack placement 2. **Use axiom-swiftui** for cross-platform SwiftUI: state management, layout primitives, animations 3. **Both may apply**: A watchOS NavigationStack with complications needs axiom-watchos for complication surfaces and axiom-swiftui for NavigationStack basics

**axiom-watchos vs axiom-integration**: For widgets and Live Activities: 1. **Use axiom-watchos** for watch complications, Smart Stack placement, watch-side Live Activity presentation, RelevanceKit 2. **Use axiom-integration** for iOS/iPadOS widgets, core ActivityKit API, App Intents

**watch-device-diag vs watch-connectivity**: Two independent connections fail in ways that look identical. Decide which before writing any code: 1. **Use watch-device-diag** for the Mac/Xcode → Watch link (CoreDevice): install, launch, LLDB attach, a Watch that is missing or `unavailable` 2. **Use watch-connectivity** for the iPhone app ↔ watchOS app link (`WCSession`): transfer-API choice, delivery semantics, background-task completion 3. **When unsure, start with watch-device-diag.** Run the app without the debugger attached — if it behaves correctly, the fault is the tunnel and no `WCSession` change will help. Redesigning `WCSession` to compensate for a broken debugger tunnel is the most expensive mistake in watchOS work 4. **`isReachable == false` is not a transport failure** — it is the expected value across ordinary lifecycle transitions and routes to watch-connectivity, not here

**axiom-watchos vs axiom-health**: For workouts on Apple Watch: 1. **Use axiom-watchos** for watch-specific presentation: Always On display, Smart Stack placement, background mode coordination 2. **Use axiom-health** for `HKWorkoutSession` lifecycle, `HKLiveWorkoutBuilder`, recovery, multi-device mirroring

Decision Tree

digraph watchos {
    start [label="watchOS development task" shape=ellipse];
    what [label="What area?" shape=diamond];

    start -> what;
    what -> "skills/platform-basics.md" [label="app structure, independent apps, submission"];
    what -> "skills/design-for-watchos.md" [label="watch HIG, glanceable UX"];
    what -> "skills/smart-stack-and-complications.md" [label="complications, Smart Stack, RelevanceKit"];
    what -> "skills/controls-and-li